Restrict Protein, Not Just Calories, to Prolong Life

[Guest guest]

Sorry I do not have direct links to the journal articles, but this is still good

informatio - a summary article by Dr. Gabe Mirkin, via his newsletter with

journal references.

DrMirkin's eZine: Restrict protein to prolong life

http://www.drmirkin.com

Recent research show that protein restriction may be far more effective

than calorie restriction in prolonging the lives of humans. Many studies show

that restricting calories prolongs the lives of yeast, worms, spiders, flies,

insects, rats and probably monkeys. Humans who severely restrict calories have

long-life characteristics, such as low cholesterol and blood pressure and hearts

that are more than 15 years younger than those of other North Americans their

age (Experimental Gerontology, August 2007).

However, most of the test group of humans who restrict calories do not

have a drop in a hormone called Insulin-Like Growth Factor-1 (IGF-1) that

appears necessary for living a long time. High blood levels of IGF-1 are

associated with premature aging and diseases of aging such as diabetes and

cancer. IGF-1 levels are lower than normal in worms, flies and mice on

restricted-calorie diets, but not in humans. This week a report shows that

IGF-1 shortens life by increasing cell DNA genetic damage, and causes cancer by

blocking apoptosis that causes cancer cells to kill themselves before they

destroy their host (Science Translational Medicine, February 16, 2011).

Luigi Fontana, a professor of medicine at Washington University in St

Louis, noticed that most calorie-restricting humans eat high levels of protein,

about 1.7 grams per kilogram of body weight/day. This is more than the US

government-recommended intake of 0.8 g/kg/day, and even higher than the 1.2

g/kg/day that the average American eats. Dr. Fontana asked humans on calorie

restricted diets to reduce their intake of protein to 0.95 g/kg/day. After just

three weeks of reduced protein intake, their IGF-1 levels dropped markedly

(Aging Cell, September, 2008).

Among the calorie-restricting humans, vegans have lower levels of IGF-1 than

meat-eaters (Rejuvenation Research, February 2007). Strict vegans also have

significantly lower IGF-1 levels than people who restrict just calories, even if

they are heavier and have more body fat. Strict vegans take in about 10 percent

of their calories from protein, whereas those on calorie restriction tended to

get 24 percent of calories from protein. Other data show that diets lower in

protein might protect against some cancers. So restricting protein may be more

important than restricting calories.

If fruit flies and rodents are fed special diets that restrict protein,

they can eat as many calories as they want and still live longer (Nature,

December 2009). This suggests that as long as you are not overweight, you may

not need to restrict calories. Instead, restrict only protein which is far

easier to do.

Furthermore, you can probably eat all the fruits and vegetables you want and

not restrict calories as long as you

restrict protein. That's very good news because it is far easier

to restrict protein than it is to restrict all foods. The only way that you can

restrict calories and still remain healthy is to eat a diet based on vegetables.

It now appears that you extend your life far more by reducing protein that you

would by restricting just calories.